The present invention relates to an absorbent article. In particular, the present invention relates to an absorbent structure for disposition as a sanitary pad, incontinent pad, infant diaper, or similar fluid absorbing article that offers a marked degree of dryness over the surface of the insult area (i.e., soiled, for example, by liquid and/or solid voiding by the wearer).
Previous attempts for achieving dry surfaces and stain resistance to the surface of absorbent pads include a number of techniques disclosed hereinbelow. Mullane et al., U.S. Pat. No. 4,324,246, relates to a hydrophobic, liquid permeable topsheet having a caliper of less than 0.030 inches, an equivalent hydraulic diameter of less than 0.025 inches, and an open area of at least 35% to 55%. Radel et al., U.S. Pat. No. 4,342,314, relates to a resilient, liquid permeable, three-dimensional plastic material that forms a capillary network from laminated layers having corresponding apertures of decreasing cross-section which promote transmission of fluid through the structure without having lateral transmission of the fluid between adjacent capillary networks. In addition, Mattingly, III et al., U.S. Pat. No. 4,690,679, discusses an absorbent product which uses a coextruded apertured film having differing melting points which enhance fluid flow to the absorbent core and prohibits flow in the opposite direction (rewet). Mattingly, III et al., U.S. Pat. No. 4,806,411, further describes a coextruded apertured film having layers with differing melting points. The apertures have an equivalent circular diameter of 0.01 to 0.03 inches with a total open area of 20% to 70%. The thickness of the film is 1 to 10 mils.
Osborn, European Patent Application 0 336 578 A1, describes a thin, flexible sanitary napkin that utilizes an apertured formed film coversheet, an apertured nonwoven, wipe acquisition sheet, and an absorbent core containing 5-35% by weight of a particulate hydrogel-forming polymer gelling agent.
Meyer et al., U.S. Pat. No. 4,798,603, describes an absorbent structure having a hydrophobic, liquid permeable topsheet, a moisture impermeable bottom sheet, an absorbent core, and a liquid permeable transport layer between the topsheet and absorbent core which is less hydrophilic than the absorbent core and has an effective pore size which is smaller than the pore size of the topsheet layer.
Kellenberger et al., U.S. Pat. No. 4,699,823, relates to an article with an absorbent layer having a superabsorbent polymer contained therein. The absorbent layer further has a z-directional superabsorbent concentration gradient. Kellenberger, U.S. Pat. No. 5,147,343, describes diapers and other specific absorbent articles having a porous fiber matrix with superabsorbent material present in the matrix so that the superabsorbent material can absorb a given amount of fluid while under a certain applied pressure. Kellenberger et al., U.S. Pat. No. 5,149,335, describes an absorbent structure which utilizes a superabsorbent material contained within a fibrous matrix or between layers of the fibrous material, having a free swell rate of less than about 60 seconds, a five minute absorbency under loads of at least 15 grams of fluid per gram of absorbent, and an amount of superabsorbent material which is 60 to 100 weight percent based on the total weight of the containment means (e.g. absorbent plus superabsorbent).
Current products which offer the feature of a marked degree of dryness over the surface of the insult area after the absorbent pad has been insulted utilize a "three dimensional" apertured film (e.g., a film that has conical or similar formed apertures) to achieve dryness. This type of plastic film typically is treated with surfactants to reduce hydrophobicity.
It is an object of the present invention to provide an absorbent article which utilizes a composite structure of a "two dimensional" or very flat, apertured film or a nonwoven layer, in combination with a layer of fluid transferring material, a superabsorbent polymer-containing laminate below the fluid transferring material and an absorbent core below the laminate to achieve dryness.
Additional objects and advantages of the present invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objects and advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.